Answer:
Slope of short-run aggregate supply curve: wage-price flexibility
In the short run, some factors are fixed and some factors can vary and the costs incurred on fixed factors are constant. Thus, the price level does not change as fast as it could have been if all are variable resources.
However, if prices are subjected to the variation in the wages, then the price level will increase faster than the costs. If actual price level is below the expected level, then the nominal wage rate is more than the expected and vice-versa. This would result in a greater slope of the short-run aggregate supply curve, which means short-run aggregate supply curve will be relatively steeper.
In the short run, the wage rate and price level are sticky downward because fall in nominal wage of workers will reduce the incentive to work.
Hence, if the wage rate adjusts continuously to any change in price; then the aggregate supply curie is relatively steep, and when wage and price level are sticky, then the short-run aggregate supply curve will be relatively flat.